1. Field of the Invention
The present invention relates to a regulating device for a central heating plant containing a hot water supply, comprising a boiler for heating a heating medium, a pipe for feeding the heating medium to space heating elements, a distribution device which is accommodated in the feed pipe and has a connection to a flow-through heat exchanger, which is also connected to a return pipe from the space heating elements to the boiler, while a pipe for tap water is provided in the flow-through heat exchanger, and said flow-through heat exchanger is provided with a thermostat which operates the distribution device and at a particular temperature switches the distributicn device to circulation of the heating medium through the flow-through heat exchanger and at another temperature to circulation of the heating medium through the space heating elements.
2. Description of the Prior Art
Such a regulating device is known for example from Dutch Pat. No. 148.697. in the heating plant described in this patent the thermostat in the flow-through heat exchanger at a temperature of about 55.degree. C. switches the three-way valve to circulation the flow-through heat exchanger and, when a temperature of about 65.degree. C. is reached, switches the three-way valve back to circulation through the space heating elements. This means that the water in the flow-through heat exchanger is kept constantly at an average value of about 60.degree. C.
On the one hand this temperature in the flowthrough heat exchanger means that, apart from heat losses in the pipe between the flow-through heat exchanger and the draw-off point, hot running water is always available immediately; on the other hand, maintaining this high temperature in the flow-through heat exchanger gives rise to considerable energy consumption, particularly during periods when no hot running water is being drawn off.